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ns: Force a defined state when sending NS RESET 

Currently the state is assumed to remain the same while the reset
procedure is active. While this works correctly in general, a single
unexpected BLOCK_ACK or UNBLOCK_ACK can change the state but will not
stop the reset procedure. The leads to repeated RESET messages, where
the corresponding RESET_ACK is ignored. This is a stable state which
can only be left by manual intervention or by reception of a RESET
message from the peer.

This commit changes the RESET timeout handler to set the state to
BLOCKED/RESET when sending the new NS RESET message.

Note that this should ensure a clean restart even if the state has been
screwed up. It does not fix the handling of BLOCK_ACK or UNBLOCK_ACK
in abnormal cases.

Addresses:
 gprs_ns.c:349 NSEI=8895 Tx NS RESET (NSVCI=8895, cause=O&M intervention)
 gprs_ns.c:878 NSVCI=8895 Rx NS RESET ACK (NSEI=8895, NSVCI=8895)
 gprs_ns.c:887 NS RESET ACK Discarding unexpected message for NS-VCI 8895 from SGSN NSEI=8895

Ticket: OW#1551
Sponsored-by: On-Waves ehf
This commit is contained in:
Jacob Erlbeck 2015-12-17 13:22:36 +01:00 committed by Holger Hans Peter Freyther
parent 5ab8e2cdfc
commit cc6ac4cdc4
3 changed files with 108 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/gb/gprs_ns.c
View File

@ -615,6 +615,12 @@ static void gprs_ns_timer_cb(void *data)
break;
case NSVC_TIMER_TNS_RESET:
rate_ctr_inc(&nsvc->ctrg->ctr[NS_CTR_LOST_RESET]);
if (!(nsvc->state & NSE_S_RESET))
LOGP(DNS, LOGL_NOTICE,
"NSEI=%u Reset timed out but RESET flag is not set\n",
nsvc->nsei);
/* Mark NS-VC locally as blocked and dead */
nsvc->state = NSE_S_BLOCKED | NSE_S_RESET;
/* Chapter 7.3: Re-send the RESET */
gprs_ns_tx_reset(nsvc, NS_CAUSE_OM_INTERVENTION);
/* Re-start Tns-reset timer */

18
tests/gb/gprs_ns_test.c
View File

@ -710,6 +710,24 @@ static void test_bss_reset_ack()
send_ns_reset_ack(nsi, nse[0], 0xf001, 0x1000);
gprs_dump_nsi(nsi);
/* Test crossing RESET and UNBLOCK_ACK */
printf("--- RESET (BSS -> SGSN) crossing an UNBLOCK_ACK (SGSN -> BSS) ---\n\n");
setup_ns(nsi, nse[0], 0x1001, 0x1000);
nsvc = gprs_nsvc_by_nsvci(nsi, 0x1001);
gprs_nsvc_reset(nsvc, NS_CAUSE_OM_INTERVENTION);
OSMO_ASSERT(nsvc->state & NSE_S_BLOCKED);
OSMO_ASSERT(nsvc->state & NSE_S_RESET);
send_ns_unblock_ack(nsi, nse[0]);
gprs_dump_nsi(nsi);
send_ns_reset_ack(nsi, nse[0], 0x1001, 0x1000);
expire_nsvc_timer(nsvc);
OSMO_ASSERT(nsvc->state & NSE_S_BLOCKED);
OSMO_ASSERT(nsvc->state & NSE_S_RESET);
send_ns_reset_ack(nsi, nse[0], 0x1001, 0x1000);
gprs_dump_nsi(nsi);
gprs_ns_destroy(nsi);
nsi = NULL;
}

84
tests/gb/gprs_ns_test.ok
View File

@ -569,6 +569,90 @@ Current NS-VCIs:
NS-VC replaced other count: 2
NS-VC changed NSEI count : 3
--- RESET (BSS -> SGSN) crossing an UNBLOCK_ACK (SGSN -> BSS) ---
Setup NS-VC: remote 0x01020304:2222, NSVCI 0x1001(4097), NSEI 0x1000(4096)
PROCESSING RESET from 0x01020304:2222
02 00 81 01 01 82 10 01 04 82 10 00
==> got signal NS_REPLACED: 0x1001/0.0.0.0:0 -> 0xf001/1.2.3.4:2222
==> got signal NS_RESET, NS-VC 0x1001/1.2.3.4:2222
MESSAGE to BSS, msg length 9
03 01 82 10 01 04 82 10 00
MESSAGE to BSS, msg length 1
0a
result (RESET) = 9
PROCESSING ALIVE from 0x01020304:2222
0a
MESSAGE to BSS, msg length 1
0b
result (ALIVE) = 1
PROCESSING UNBLOCK from 0x01020304:2222
06
==> got signal NS_UNBLOCK, NS-VC 0x1001/1.2.3.4:2222
MESSAGE to BSS, msg length 1
07
result (UNBLOCK) = 1
PROCESSING ALIVE_ACK from 0x01020304:2222
0b
result (ALIVE_ACK) = 0
MESSAGE to BSS, msg length 12
02 00 81 01 01 82 10 01 04 82 10 00
PROCESSING UNBLOCK_ACK from 0x01020304:2222
07
==> got signal NS_UNBLOCK, NS-VC 0x1001/1.2.3.4:2222
result (UNBLOCK_ACK) = 0
Current NS-VCIs:
VCI 0xf001, NSEI 0x1000, peer 0x00000000:0, blocked
NS-VC Block count : 1
NS-VC replaced other count: 2
VCI 0x2001, NSEI 0x2000, peer 0x01020304:1111
VCI 0x1001, NSEI 0x1000, peer 0x01020304:2222
NS-VC Block count : 4
NS-VC replaced other count: 3
NS-VC changed NSEI count : 4
PROCESSING RESET_ACK from 0x01020304:2222
03 01 82 10 01 04 82 10 00
result (RESET_ACK) = 0
MESSAGE to BSS, msg length 12
02 00 81 01 01 82 10 01 04 82 10 00
PROCESSING RESET_ACK from 0x01020304:2222
03 01 82 10 01 04 82 10 00
MESSAGE to BSS, msg length 1
0a
result (RESET_ACK) = 1
Current NS-VCIs:
VCI 0xf001, NSEI 0x1000, peer 0x00000000:0, blocked
NS-VC Block count : 1
NS-VC replaced other count: 2
VCI 0x2001, NSEI 0x2000, peer 0x01020304:1111
VCI 0x1001, NSEI 0x1000, peer 0x01020304:2222, blocked
NS-VC Block count : 5
NS-VC replaced other count: 3
NS-VC changed NSEI count : 4
Current NS-VCIs:
--- Setup SGSN connection, BSS -> SGSN ---